Multiple pole plug



July 22, 1941. w. HERMAN 2,249,827

MULTIPLE POLE PLUG Filed Oct. 8, 1938 2 Sheets-Sheet 2 INVENTOR ATTORNEY Patented July 22,

UNITED STATES PATENT. OFFICE 4 Claims.

This application is a continuation in part of the applicants copending application Serial No. 73,901, flied April 11, 1936, now Patent No. 2,191,385, dated February 20, 1940.

My present invention relates to contact plugs and more particularly to a multiple pole plug.

The principal object of the present invention is to provide a multiple pole plug having an integral, one-piece, plug body of resilient material in which the contact blades are self-anchored.

Another object of the'present invention is to provide a multiple plug construction in which the cord and blade can be assembled outside of the plug body.

A further object of the present inven on is to provide a multiple plug in whichthe cord, blade,

and plug body are so assembled that they will withstand heavy use and great strain.

An additional object is to provide a plug body having the above advantages, which is easy and economical to manufacture and to assemble.

Another object of the present invention is to detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claims appended hereto.

In the drawings,

Fig. l is a front view of a completelyassembled range plug embodying my invention;

Fig. 2 is a side view thereof;

Fig. 3 is a rear view thereof, the cover being removed;

Fig. 4 is a section taken along line 4-4 of F 1;

Fig. 5 is a plan view of the cover;

Fig. 6 is an edge view thereof;

Fig. 7 is a perspective view of a contact blade;

Fig. 8 is a plan view of the blade. and cord assembly; I

Fig. 9 is a vertical section -of the plug body with the cable inserted and the blade ready for assembly; I h

Fig. 10 is a sectional view ofanother form of my invention;

Fig. ll-is a front view thereof;

Fig. 12 is .a perspective view of the cord and blade assembly used for the form shown in Figs. 10 and 11; and

Fig. 13 is a section taken along line l8-l3 of Fig. 10.

While the present invention can readily be applied to any type of multiple pole plug, for purposes of illustration only, I have herein described and shown the invention as applied to a three pole range plug.

Referring in detail to the drawings illustrating my invention, the numeral [0 generally designates the plug body, which is made of suitable insulating material, preferably resilient rubber,

which is provided with a neck ll adapted to hold the electrical cord or cable. The plug body may be of any suitable size and shape, but is preferably of diamond shape as shown in Fig. 1, and the neck ll preferably extends from one corner of said plug body. The front of the plug body is preferably provided with three circular bosses l2, II, and 14 arranged as shown in Fig. 1. Extending vertically through the upper circular portion I2 is a slot II to receive the contact blade i8, and extending through the lower circular portions i3 and] 4 respectively are angularly disposed slots l1 and I8 for the. contact blades l9 and 20. The spacing of the slots and blades shown in Fig. 1 is standard; the upper blade I 8 is slightly longer than the lower blades and is straight, as illustrated, to form the ground connection, and the lower blades are shorter than the upper blade and have ridges-2i adjacent the tips thereof for providing a firm frictional electrical contact with the usual socket connection.

The body portion iii of the plug is provided (Figs. 3 and 4) with a cut out housing 22 communicating with the neck H and forming the cable passageway, and has converging grooves 23,

24, and 25 which respectively extend from the rear of the slots II, I! and It to the housing 22.

To facilitate assembly of the type of plug shown in Figs. 1 to 4 inclusive, the back of the plug body is preferably open, a cover 28 being provided and having a groove 21 and an abutting portion 28 extending around the periphery thereof, the cover being adapted to lock into the back of the plug body It, the groove 21 receiving the extended lip of the plug body opening 29 and the abutment 2! extending into a groove 30 around the inner edge of the plug body.

The plug body [0 is preferably molded of resilient rubber or other suitable material in the manner shown and described in my application Serial No. 90,042, entitled Method of making contact plugs, illed July 11, 1936. with this con- "struction, the slots ii, I], and I8 each have a substantially wide slot portion ll, shoulders 32, a restricted slot area 33, shoulders 34, and another substantially wide slot portion ll which communicates with the grooves 23, 24, and 24 respectively. The widths of the slots are substantially identical with the widths of the contact blades to be used in the slots, so that the blades can set ilrmly within the slots without distorting the plug body, the shoulder portions 32 and 34 cooperating with and interlocking with corresponding shoulders on the contact blades to positively lock the contact blades within th plug body.

This cooperation engagement between the erably at substantially right angles to the contact blade. However,.it is more advantageous in different types of installations to have the electrical cord cable in line with the contact blade. Forthis I have devised the construction shown in Figs, to 13 inclusive.

Referring to Figs. 10 and 11, the plug body 42 is preferably circular and comprises a flat front portion 43 having bosses 44 corresponding to similar portions in the form shown in Fig. 1, and

- having slots 45 and blades 48' similarly disposed contact blade and the shoulder portions in the 1 plug body is more fully described in my copending applications Serial Nos. 22,506 and 73,901, entitled respectively Contact plug and Contact plugs, flied May 21, 1935, and April 11, 1936, now Patents Nos. 2,191,384 and 2,191,385 respectively, dated February 20, 1940, in which the eificacy and strength of this type of construction ar described.

While any suitable contact blade may be used having anchoring means such as struck up lugs or the like, I prefer to us the blade construction shown in Fig. '7. In this construction, the contact blade consists of a main body portion 36 having an opening 31 for engagement by the pull arms of the assembly machine, and a shoulder portion 38, a substantially narrower body portion 39, terminating in a shoulder portion dd, anda head it. The head 4! receives the electrical cord connection and is split in three as shown inFig. 7, the two outer portions forming prongs-slightly curved forwardly, and the middle portion curved in the opposite direction so that when an electrical cord connection. is placed therebetween, as shown in dotted lines in Fig, 7, it is eflectively gripped and held by. the contact blade. For further security, the electrical cord connection may be spot welded to the central prong as shown at 4m in Fig. 4.

As shown in Figs. 1 to 4, the electrical cord connection is preferably at right angles to the contact blade. This assembly is shown in Fig. 8, wherein each contact blade is attaehed'to its electrical cord connection in the manner just described. In assembly, the contact blades are first fixed to the electrical cord connection and the electrical cord is pulled through from the back of the plug body through the neck II as shown in Fig. 9. To take up the strain on the cable, the neck II is preferably V; of an inch less in diameter than the cable. By using a machine of the type shown and described in application Serial No. 99,848, entitled Connector plug assembly apparatus, flied September 8, 1936, the contact blades may be pulled into their respective slots and effectively anchored therein as shown in Fig. 4.

In assembled position the contact blades and cord take the position shown in Fig. 3, with the individual electrical cord wires leading to each contact blade flatly disposed in their respective grooves. The insulating material between the grooves separates the bare ends of the cord lead therein. The plug body 42 is preferably tapered towards the rear as indicated at 41, and ends in a rim or lip 48.

Acabie opening 49 extends through the rear portion of the plug body 42 and opens into a cable receiving chamber 59 which has three diverging passageways 5i connecting with the slots 45 in which the contact blades are anchored. As in the previous form, the cable opening 48 is preferably $4; of an inch less in diameter than the cable. This will firmly anchor thecabie against strains as provided by the underwriters tests.

The dielectric material between the diverging passageways 5! forms a plurality of conical baffies eifectively separating the bare ends of the cable wires and preventing high amperage arcing and short circuiting. I

Referring to Fig. 12, I prefer to use a modified form of contact blade as shown therein, the rear portion of the contact blade being provided with a U-shaped cut out into which the cord lead wire can be anchored and spot welded as at 52. The contact blades are preferably spot welded to the cord lead wire in line therewith so that, see Fig. 10, when the contact blade, cord, and plug body are assembled, the cable will extend out of the plug body in line with the contact blade.

The form shown in Figs. 10 to 13 inclusive is assembled on the assembly machine hereinbefore referred to, but there is no preliminary insertion of the cables, as is required for the form shown in Figs. 1 to 4 inclusive. The plug body is merely placed into the machine and the blade and cord lead wire are pulled into the slots, whereby the corresponding shoulders and abutments on the contact blades and the slots will effectively lock the blades in the plug body.

The form shown in Figs. 10 and 11 also corresponds to standard multiple plug contact blades, the upper blade being straight and slightly longer than the two lower blades and the two lower blades being disposed at opposite angles and having the usual ridges near the tips thereof.

The plugs in both frames can obviously be made with 4, 5, or any number of poles, and as hereinbefore described, are simple in construction and easy and economical to manufacture and assemble. They can be made of resilient materials such as soft rubber and will withstand hard strain, pulls, and knocks, and will effectively pass all tests necessary for strength, dielectric properties, and short circuiting, required for this type of article.

While I have described specific constructional embodiments of my invention, and specific methods for assembly, it is obvious that these are merely illustrative, and that changes in the size theinvention as defined in the appended claims.

Iclaim:

1. In a plug construction, a one-piece plug body of resilient material having a cable opening through one end thereof and three grooves in the upper surface for individual leads extending divergently from said cable opening, said body having three rectangular transverse blade passageways terminating in the said grooves and adapted to receive fiat rectangular contact blades having restricted portions adjacent their head ends, said passageways each having opposed constrictions intermediate the passageway ends adapted to seat in the blade head end restricted portions.

2. In combination, a one-piece plug body of resilient material having a cable opening through one end thereof and three grooves in the upper surface for individual leads extending divergentiy from said cable opening, said body having three rectangular transverse blade passageways terminating in the said grooves and adapted to receive flat rectangular contact blades therein, flat, rectangular, contact blades having head ends and seated in said passageways, said blades having restricted portions adjacent their head ends, said passageways each having opposed constrictions intermediate the passageway ends adapted to seat in the blade head and restricted portions,

and a cable in said cable opening having leads in said grooves secured to the blade head ends.

3. In a plug construction, a one-piece plug body of resilient material having a cable opening through one end thereof and three grooves for individual cord leads extending divergently from opening, said grooves terminating in three spaced rectangular blade passageways adapted to receive flat rectangular contact blades therein, flat, rectangular, contact blades having head ends and seated in said passageways, said blades having restricted portions adjacent their head ends, each passageway having opposed-constrictions intermediate the passageway en'ds adapted to seat in the blade head end restricted portions, and a cable in said cable opening having leads in said grooves secured to the blade head ends.

, WILLIAM P. HERMAN. 

